So not many hearts or minds have been changed by Oscar's testimony. I suspect that those who already found him guilty would be smearing him no matter how he came across on the stand.
But I think the state failed to present a convincing case for premeditated murder anyway.
I think you're 100% wrong.
I think a lot of people see the killer as an even more manipulative, self-serving liar than before.
And walking to get a gun, moving towards the victim, yelling at the victim and then shooting a the victim after the victim retreated IS the definition of premeditated murder.
That's why the killer is testifying to try to convince the judge his admitted killing of the victim is not a violation of the law.